It's happened to us at one time or another. You run out of battery power on your cellphone, without a power outlet to be found. Or worse, you lose your cell phone charger. And, of course, it happens when you are in the middle of an important call. Or a really awesome game of Words with Friends.

Imagine if all you needed were the sound of your voice to charge your phone. That is crazy talk!

But that may be a possibility one day, because researchers in South Korea are developing a system that converts sound to energy. This technology would allow cellphones to recharge as people speak into their phones.

The researcher leading this project is Sang-Woo Kim of the Institute of Nanotechnology at Sungkyunkwan University in Seoul, South Korea.

In an interview with The Telegraph, Kim said the sound that exists in our everyday lives has been overlooked as a source of energy.

Kim said a cellphone could be charged by speaking into the device, and could also be powered by background noise. This process of powering mobile devices is referred to as "energy scavenging."

The technology generates a current through zinc oxide wires placed between two electrodes. A pad placed on top absorbs sound, which causes the zinc oxide wires to compress and release. This, in turn, generates an electric current, which can be used to charge a battery.

I can see this as a convenient feature when it does become a reality and available for all. Just yell at your phone when your battery is low. Most of us do that anyway. Think of all that energy we are wasting. Soon, we can put all that shouting to good use.